If your dog eats a stone or stones then you should monitor his condition carefully and consider taking him to the vets.
Small stones may pass through your dog’s system easily and be discharged when he goes to the toilet but there is no way to be sure that this will happen.
Larger stones could become stuck inside your dog and could cause a serious blockage either in his throat after he swallows them or further on in his intestines.
It is always advisable to speak with your vet if you notice that your dog has swallowed a stone or if you suspect that he has.